If you have exported your Xerte project by selecting your project in the workspace, selecting properties and then one of the export options and have the resulting zip file it's definitely not a database. So whoever has said that is mistaken. However that zip does contain multiple files and folders including a media folder so it isn't just a single html file and needs to be uploaded and extracted or extracted and then all the extracted files and folders uploaded. Applications like Dropbox and Google Drive used to allow uploading of the files and folders and then making the index.htm a public link but I don't think they allow that any longer - at least not in a way that allows everything to work.
You need space on a web server and there is plenty of cheap hosting about although cheap hosting can be a false economy if you need reliability or don't have the technical skills or time for maintenance. You could try a free aws account
aws.amazon.com/free
but setting that up is a bit technical. If you have a budget there are also options for signing up for access to a shared xerte installation where you could import your project, make it public and share the link via your intranet site but that would mean that users would need web access when they click the link on the intranet.
HTH
Ron